Metabolic Rate System

[rsaavedra]

I have been reading the thread for a while now and overall the idea is fantastic.There are some sentences that I’m not understanding very well or aren’t written with the most scientificly correct terminology. I think overall it’s clear what the idea is, though I will try to correct/pinpoint some sentences.

@Deus

Each cell then breaks down nutrients locally, using respiration to breakdown nutrients

This is written vaguely, respiration exclusively converts glucolitic metabolites and derivates into CO2 generating a potential capable of reconverting ADP into ATP, but the whole process of breaking down e.g. Proteins and Polysaccharides into amino acids and simple sugars, respectively, involves quite a lot of metabolic paths and not only respiration. Probably a better idea would be that nutrients are fully oxidized, wether it is by aerobic respiration or any other metabolic pathway. I know you want to keep it simple and straight to the point.

@Deus

Let’s say you are a high-speed predator. You don’t eat all the time, but when you do eat, you eat a lot, and you spend a lot of energy getting that food. You also maintain a lot of high-energy adaptations, such as fast-twitch muscles and an extensive respiratory system. Considering this, it would probably benefit you to breakdown food very quickly, even if it means a loss of efficiency. If you breakdown whatever food you got slowly, you might not have enough nutrients available to fuel the moments in which you burst for prey.

Yeap, here comes the concept of Lactic Acid and the balance between aerobic respiration and lactic fermentation. I don’t know if you are familiar with these https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Chemistry_for_Allied_Health_(Soult)/15%3A_Metabolic_Cycles/15.03%3A_Lactic_Acid_Fermentation (the next step would be the Cori cycle Cori cycle - Wikipedia, which I already commented here New organelle for storing ATP as glucose as Gluconeogenesis - ATP usage to glucose recovery - is strongly related to the Lactic Acid Fermentation, through the Cori cycle). So really nice idea there.

@Deus

In Thrive, your digestive rate will determine how quickly your organism breaks down organic matter into nutrients. You can generally influence either the rate or efficiency of digestion to suit your playstyle, through means that I will propose in another post.

Yeap, keeping it simple without losing scientific accuracy.

@Deus

Respiration Rate = Oxygen is needed as a catalyst for cellular respiration, serving as a controlled explosion of energy. Cells convert whatever nutrients they receive locally, meaning they also need local availability of adequate oxygen. Though there is some exchange between the rate and efficiency of respiration, a lot more emphasis is placed on adaptations which influence the efficiency of respiration. A more efficient respiration rate allows a quicker breakdown of nutrients into readily accessible energy.

Organisms which require a rapid burst of energy or live in low-oxygen environments, such as high elevations or the deep oceans, generally require elevated respiration rates to support their lifestyle. However, there is a certain point where the marginal benefit of extra oxygen absorbed does not justify the marginal cost of additional metabolic costs. This is why you don’t see every single organism in high oxygen environments maintain a hyper-powered respiratory system. It also means that even in low oxygenic environments, there is only a certain amount of oxygen available to be extracted.

Again here you take into account only the aerobic respiration and usage of O2 as electron acceptor (maybe I got a bit technical here ), and, even though as we know today all eukaryotic/large organisms use aerobic respiration we can’t know what would evolution bring out in another planet.

@Deus

Here is some more reading on respiration rates and size: Oxygen Consumption in Relation to Body Size, Wave Exposure, and Cirral Beat Behavior in the Barnacle Balanus Glandula | Journal of Crustacean Biology | Oxford Academic

Pretty cool, though this probably will arise naturally once the ATP consumption is balanced and proportional to the number of cells/mass.

@Deus

In Thrive, your respiration rate will influence how quickly your nutrients are broken down into energy/ATP. Various factors can influence respiration rate, including surface area and dedicated organs. Your respiration rate will ultimately be limited by the amount of available oxygen in your environment.

A lot of oxygen does not necessarily translate into a quicker respiration. And there are problems when respirating too much, during the 80’s the leading theory about why do we age was that too much oxygen destroyed our cells and it is partially true, so … yeap, too much oxygen is not necessarily beneficial either. I would say that the oxygen avaliability is a crucial factor to the organism’s size/mass.

@Deus

Circulation Rate = Your circulation rate is essentially how fast things that need to get somewhere go in the body. Everything from water concentration, to nutrient circulation, to respiration is heavily dependent on circulation. Most smaller or less complex organisms don’t necessarily need an elaborate or dedicated circulatory system - many jellyfish, for example, get enough circulation from their digestive system to support their (relatively) low energy lifestyle. However, as complexity and size increases, there is a greater need for a more high-powered circulatory system

Yeap pretty much it, nice

@Deus

In Thrive, your circulatory rate will essentially act as a coefficient affecting either your digestive or respiration rates (or both, though some adaptations might focus more on a specific rate). This coefficient might be neglected at first, but as you get more complex, you will need to supplement your digestive and respiratory rates to meet increasing energy demands.

I’d reccomend to take a look to Camel’s blood cells Blood Cells Protect From Dehydration — Biological Strategy — AskNature and Kleiber’s paradox (now law) Kleiber's law - Wikipedia.

@Deus

we should probably rename “organic matter” to be more neutral for the brief period in time where quirky diets might exist early on; it’s ingested matter currently, yes?

Alright

@Deus

• Ingested matter becomes nutrients dependent on your digestive rate, which is affected by your circulation rate.
• Nutrients turn into ATP/energy dependent on your respiration rate, which is affected by your circulation rate.

Perfect

Well, I hope the feedback is useful , feel free to ask/comment me anything.